(a) A person commits the crime of graffiti if he marks the exterior face of any public property, including roads, buildings, and equipment, with any figures, drawings, or other writings, using paint lacquer, varnish, dye or other substance intended to last on such exterior face for more than 24 hours.

(b) Graffiti prohibited by subsection (a) is not an offense if committed under the supervision of public officials who authorize such figures, drawings or writing as part of a beautification project.

(c) Graffiti is punishable, at the discretion of the court, as follows;

(1) as a class B misdemeanor or

(2) by ordering the defendant to do a fixed number of hours of community service work cleaning public property defaced by graffiti.